A traditional technique for comparing a first linguistic item (such as a query) with a second linguistic item (such as a document) is to directly compare terms in the first linguistic item with the terms in the second linguistic item. In some cases, however, the two linguistic items may use different words to express the same concept. The traditional technique may produce unsatisfactory results in these circumstances.
To address the above drawbacks, the research community has proposed techniques which project linguistic items to a higher-level semantic space, and then compare the linguistic items in that space, rather than (or in addition to) comparing the lexical “surface” forms of the linguistic items. For example, a technique may use the well-known Latent Semantic Analysis (LSA) technique to perform the above-described kind of processing.
The above-described types of latent analysis techniques have, in some cases, improved the quality of linguistic analysis. Yet there remains room for further improvement in this field of research. For instance, known latent analysis techniques often produce unsatisfactory results in those cases in which linguistic items use similar words, but in different respective contexts.